Question

如何传递一些参数，这些参数将在.cl文件中作为预处理器使用pyopencl进行定义？

含义：

foo.cl

# define LIMIT 12
typedef struct {
    uint i[LIMIT];
} foomatic;

转向

foo_nodefs.cl

typedef struct {
    uint i[LIMIT]; // python script passing LIMIT to set it
} foomatic;

谢谢，

约翰

Answer 1

编辑：扩展答案，使其最详细。

有两种方法可以做到：

（元编程）使用源代码将预处理程序指令直接添加到字符串，甚至使用某些模板引擎运行自己的预处理程序。

import pyopencl as cl
import numpy
import numpy.linalg as la

a = numpy.random.rand(50000).astype(numpy.float32)
b = numpy.random.rand(50000).astype(numpy.float32)

ctx = cl.create_some_context()
queue = cl.CommandQueue(ctx)

mf = cl.mem_flags
a_buf = cl.Buffer(ctx, mf.READ_ONLY | mf.COPY_HOST_PTR, hostbuf=a)
b_buf = cl.Buffer(ctx, mf.READ_ONLY | mf.COPY_HOST_PTR, hostbuf=b)
dest_buf = cl.Buffer(ctx, mf.WRITE_ONLY, b.nbytes)

defines = """
    #define AXIS 0
    #define COEFF 1
    """

prg = cl.Program(ctx,
    defines +
    """
    __kernel void sum(__global const float *a,
    __global const float *b, __global float *c)
    {
      int gid = get_global_id(AXIS);
      c[gid] = a[gid] + b[gid] + COEFF;
    }
    """).build()

prg.sum(queue, a.shape, None, a_buf, b_buf, dest_buf)

a_plus_b = numpy.empty_like(a)
cl.enqueue_copy(queue, a_plus_b, dest_buf)

print(la.norm(a_plus_b - (a+b+1)), la.norm(a_plus_b))

（C-way）使用options Program.build关键字将构建选项直接传递给clBuildProgram()：

import pyopencl as cl
import numpy
import numpy.linalg as la

a = numpy.random.rand(50000).astype(numpy.float32)
b = numpy.random.rand(50000).astype(numpy.float32)

ctx = cl.create_some_context()
queue = cl.CommandQueue(ctx)

mf = cl.mem_flags
a_buf = cl.Buffer(ctx, mf.READ_ONLY | mf.COPY_HOST_PTR, hostbuf=a)
b_buf = cl.Buffer(ctx, mf.READ_ONLY | mf.COPY_HOST_PTR, hostbuf=b)
dest_buf = cl.Buffer(ctx, mf.WRITE_ONLY, b.nbytes)

prg = cl.Program(ctx, """
    __kernel void sum(__global const float *a,
    __global const float *b, __global float *c)
    {
      int gid = get_global_id(AXIS);
      c[gid] = a[gid] + b[gid] + COEFF;
    }
    """).build(options=['-D', 'AXIS=0', '-D', 'COEFF=1'])

prg.sum(queue, a.shape, None, a_buf, b_buf, dest_buf)

a_plus_b = numpy.empty_like(a)
cl.enqueue_copy(queue, a_plus_b, dest_buf)

print(la.norm(a_plus_b - (a+b+1)), la.norm(a_plus_b))

（我使用了PyOpenCL文档主页中的修改源代码。在pyopencl 2013.1上测试过。）

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